Ecological study of Bacteroides species habored in the intestine of laboratory animals.

Principal Investigator

ITOH Kikuji Graduate school of Agriculture and Life science, The University of Tokyo, Associate Professor, 大学院・農学生命科学研究科, 助教授 (50100045)

Co-Investigator(Kenkyū-buntansha)

ITOH Tishio Central Institute for Laboratory Animals, Research Head, 室長 (20106644)
HIRAYAMA Kazuhiro Graduate school of Agriculture and Life science, The University of Tokyo, Accist, 大学院・農学生命科学研究科, 助手 (60208858)
TAKAHASHI Eiji Graduate school of Agriculture and Life science, The University of Tokyo, Profes, 大学院・農学生命科学研究科, 教授 (50183439)

Total 1,080 isolates of Bacteroidaceae from cecal contents of mice, rats, rabbits and guineapigs were identified by biochemical tests. Untypable-1 group was isolated at the predominant level from all mice except one of NC mice. IN CF#1 mice, B.vulgatus was dominant species. Untypable 1,2,3 groups but not "fragilis" group and other groups were isolated from NC mice. In two of three BALB/c mice, B.fragilis were isolated. In rat cecal contents, untypable-1 group was not detected and B.vulgatus and B.fragilis were predominant species and B.eggerthii and B.splanchnicus were followed. In guinea-pigs, B.vulgatus were the predominating species and isolated from all guinea-pigs. B.uniformis and B.fragilis were also isolated from one of three guinea-pigs respectively. A lot of species of Bacteroides were harbored in rabbit intestine as compared with other animal species. B.ovatus, B.thetaiotaomicron, Rikennera microfusus were isolated from only rabbits. In rabbits B.vulgatus, B.uniformis and B.fragilis were the predominating species and B.ovatus, B.eggerthii were the dominant. There were some differences on biovor level of B.vulgatus between mouse and rat isolates.In pig-flora-associated mice which were produced by oral inoculation with pig feces to germfree mice, "fragilis" group occupied as same as normal mice and B.suis which was the predominant species in pig intestine were not isolated. These data indicate that animals can select the most suitable Bacteroides species.